B

534 CHINESE JOURNAL OF FOOD HYGIENE 2011 23 6 100021 25% 2-5% 60 mmol / L 0. 1% 2- Supelco C 18 150 mm 4. 6 mm 5 μm KBH 4 0. 7 μg / L 4. 6% O657. 7 B 1004-8456 2011 06-0534-06 Determination of methylmercury in seafood by HPLC coupled with hydride generation and AFS Zhao KaiYang Dajin National Institute for Nutrition and Food SafetyChina CDCBeijing 100021China Abstract Objective A high performance liquid chromatography HPLC coupled with hydride generation and atomic fluorescence spectrometry is proposed for the determination of methyl mercury in seafood. Methods Samples were extracted by 25% potassium hydroxide and the methylmercury-thiol complex was separated on a Supelco C 18 150 mm 4. 6 mm5 μm reverse phase column and online UV-digested. After reduced to element Hg by KBH 4 the element Hg was selectively detected by AFS in an Ar / H 2 flame under optimized conditions. Results The detection limit for methyl mercury was 0. 7 μg / L as mercury with a relative standard deviation RSD of lower than 4. 6%. Two standard reference materials were applied for the accuracy of study. Conclusion The content of methylmercury in seafood can be determined by the method with good conveniencerapidity and reliability. Key words Seafood methyl mercury high performance liquid chromatography atomic fluorescence spectrometry hyphenated technique food contaminants food safety HPLC-AFS HPLC-ICP-MS 1 HPLC-ICP-MS HPLC-AFS 2 3 9 10 4 - AFS 5 HPLC-ICP- HPLC-AFS 2- MS 6-8 11 C 18 2011-03-07 E-mail kaizhao-83@ 163. com HPLC-AFS - HPLC-AFS

535 1 1. 1 Labtech AFS-9800 100 μl 1. 2 1-4 Figure 1 Schematic illustration of HPLC-AFS 7. 5 ml 25% W / V Sigma-Aldrich 1 min 1 mg / ml 4 70 30 min FAPAS Canned Fish T0797 FAPAS Canned Fish T07115 Food and Environment Research Agency 1. 3 50 ml 0. 45 μm 1. 3. 1 HPLC-AFS 0. 010 0 g 100 ml 1 ml 100 ml 2 1 mol / L HCl 2. 1 100 10 μg / ml4 2. 1. 1 3 1. 3. 2 5% - 50 20 10 5 5 ~ 12 min 2 μg / L 1. 4 1. 4. 1 5% - Supelco Discovery C 18 150 mm 4. 6 mm 5% 5 μm 5% 60 mmol / L 5% 1 0. 1% 2-2 5% 1. 5 ml / min 25 20 μl 1. 4. 2 2% + 0. 5% 1 Table 1 Influence of different organic solvent 5% > 99. 999% concentrations on methyl mercury peaks 300 ml / min 800 ml / min min 50 r / min 60 ma 30 ma - 300 V 1 1. 5 1. 5. 1 2. 1. 2-20 AFS 30 min 3 25 ml 1% 2-5 ml 5% 5% 20% 10% 5% 6 ~ 8 1. 5 5% 8 ~ 10 1. 0 1. 5. 2 5 g 50 ml 11 12 Margetinova

536 CHINESE JOURNAL OF FOOD HYGIENE 2011 23 6 Hg 2 + 3 A 5% B 5% 2 Figure 2 Chromatogram of methyl Hg and Hg 2 + 2% KBH 13 2-4 + 0. 5% NaOH 5% HCl 50 ~ Hg 100 r / min Hg 2-50 60 70 80 100 r / min 4 50 r / min 2-60 r / min 2-50 r / min 2- Ramalhosa 14 2-0. 000 7% ~ 0. 5% < 3% 2-0. 01% 0. 1% 5% 0. 01% 0. 1% 2-4 2- Figure 4 Effect of the rotation speed of peristaltic pump on 0. 1% 2- hydride generation 2. 2 Figure 3 a b 2. 2. 1 2. 3. 1 Hg 2 + AFS KBr / KBO 14 3 K 2 S 2 O 8 K 2 Cr 2 O 7 3 Peaks before and after oxidants device applied 2. 2. 2 2. 3

537 y = 240 761x - 334 498 r = 0. 999 4 15 25% 25% 5 5 mol / L Ortiz 16 0. 1 mol / L FAPAS Canned Fish T0797 FAPAS Canned Fish T07115 25% 5 mol / L 0. 1 mol / L 70 3 25% ph Reyes 15 5 Figure 5 Chromatogram of standard methyl Hg compound 50 μg / L 2. 3. 2 ph ph 2. 4. 2 Margetinova 13 ph 3 ~ 5 ph 6 RSD 2. 9% 4. 6% 4 ph 4 Table 4 Repeatability of the method n = 6 ph 3 ~ 5 μg / kg RSD % 78. 8 80. 4 78. 6 2 2. 9 2 Table 2 Comparison of the efficiency extracted by acid extractionand alkali leaching μg / kg T07115 136 138. 2 ± 4. 2 125. 7 ± 7. 8 T0797 487 473. 0 ± 6. 8 431. 0 ± 8. 4 3 0. 7 μg / L Reyes 15 3 FAPAS Canned Fish T07115 2. 4. 3 1 ~ 3 3 FAPAS Canned Fish 99% 3 97. 1 ± 1. 4 % 3 99. 1 ± 1. 2 % 2 Table 3 The efficiency of extraction with different 2. 4. 4 frequencies n = 3 μg / kg % 1 114. 4 ± 8. 5 84. 1 ± 6. 2 FAPAS Canned 2 123. 5 ± 3. 5 90. 8 ± 2. 6 Fish T0797 FAPAS Canned Fish T07115 3 134. 8 ± 1. 6 99. 1 ± 1. 2 5 2. 4 2. 4. 1 3 2 5 10 20 25 50 μg / L HPLC-AFS 77. 9 76. 0 74. 0 283 269 250 279 258 259 4. 6

538 CHINESE JOURNAL OF FOOD HYGIENE 2011 23 6 Table 5 5 Methyl mercury content in seafood μg / kg n = 3 T07115 136 ± 59 T0797 473. 0 ± 6. 8 1 279 ± 12. 9 2 16. 0 ± 1. 1 79. 9 ± 2. 3 1 11. 6 ± 1. 0 2 5. 22 ± 0. 7 19. 8 ± 1. 7 6. 3 ± 0. 7 6. 8 ± 0. 47 Figure 7 A B 7 Chromatograms of two samples Figure 6 A T07115 B T 0797 6 Chromatogram of standard reference materials 2- HG-AFS Chim Acta 2004 505 247-254. 7 CHANG L F JIANG S J HPLC-AFS A 2007 1176 143-148. Hg 2 + 8 WANG Meng FENG Weiyue SHI Junwen 1 ZHOU H YWONG M H. Mercury accumulation in freshwater fish with emphasis on the dietary influencej. Water Res 2000 34 17 4234-4242. 2 MAY K STOEPPLER M REISINGER K. Studies in the ratio of total mercury / methylmercury in the aquatic food chain J. Toxicol Environ Chem 1987 13 153-159. 3. GB / T 5009. 17 2003 S. 2003. 4 TSENG C M DIEGO A MARTIN F M et al. Rapid determination of inorganic mercury and methylmercury in biological reference materials by hydride Generation cryofocusing atomic absorption spectrometry after open focused microwave-assisted alkaline digestionj. J Anal Atom Spectrosc 1997 12 743-750. 5 SALIH B SAY R DENLIZLI A et al. Determination of inorganic and organic mercury compounds by capillary gas chromatography coupled with atomic absorption spectrometry after preconcentration on dithizone-anchored poly ethylene glycol dimethacrylate-hydroxyethylmethacrylate microbeadsj. Anal Chim Acta 1998 371 177-185. 6 HARRINGTON C FMERSON S ADSILVA T M. Method to reduce the memory effect of mercury in the analysis of fish tissue using inductively coupled plasma mass spectrometryj. Anal SAHAYAM A C. Speciation analysis of mercury and lead in fish samples using liquid chromatography inductively coupled plasma mass spectrometryj. J Chromatogr et al. Development of a mild mercaptoethanol extraction method for determination of mercury species in biological samples by HPLC-ICP-MSJ. Talanta 2007 71 5 2034-2039. 9 LI Naliang JIANG Guibing LIU Jinfu et al. Speciation analysis of mercury in seafood by using high-performance liquid chromatography on-line coupled with cold-vapor atomic fluorescence spectrometry via a post column microwave digestion J. Anal Chim Acta 2003 477 131-137. 10WEST G. Determination of methylmercury compounds in foodstuffsⅠ. Methylmercury compounds in fish Identification and determination J. Acta Chemica Scandinavica196620

- 539 2131-2137. 11SEGADE S R TYSON J F. Determination of methylmercury and inorganic mercury in water samples by slurry sampling cold vapor atomic absorption spectrometry in a flow injection system after preconcentration on silica C18 modifiedj. Talanta 2007 71 4 1696-1702. 12SáNCHEZ D MMARTIN RMORANTE RMARTIN J. Preconcentration speciation method for mercury compounds in water samples using solid phase extraction followed by reversed phase high performance liquid chromatography J. Talanta 2000 52 4 671-679. 13MARGETINAVA JHOUSERAVA-PELCOVA PKUBAN V. speciation analysis of mercury in sediments zoobenthos and river water samples by high-performance liquid chromatography hyphenated to atomic fluorescence spectrometry following by solid phase extractionj. Anal Chim Acta 2008 615 115-123. 14RAMALHOSA ESEGADE S RPEREIRA Eet al. simple methodology for metylmercury and inorganic mercury determination by high performance liquid chromatography-cold vapour atomic fluorescence spectrometryj. Anal Chim Acta 2001 448 135-143. 15REYES L HMIZANUR R G MFAHRENHOLZ Tet al. Comparison of methods with respect to efficiencies recoveries and quantitation of mercury species interconversions in food demonstrated using tuna fishj. Anal Bioanal Chem 2008 390 8 2123-2132. 16ORTIZ A I CALBARRAN Y MRICA C C. Evaluation of different sample pre-treatment and extraction procedures for mercury speciation in fish samplesj. J Anal At Spectrom 2002 17 1595-1601. - 1 2 1 1 1 1 1. 100050 2. 100021 - UPLC-MS / MS C 18 2 mmol / L ESI MRM 82% ~ 115% 76 ~ 129 pg / g 88 ~ 319 pg / g 9 UPLC-MS / MS O657. 72 X836 B 1004-8456 2011 06-0539-05 Quantitative determination of perfluorooctanesulfonate and perfluorooctanoic acid in animal food by UPLC-MS / MS Liu JiayingWang YuxinLi JingguangZhao YunfengWu Yongning National Institute of Nutrition and Food SafetyChinese Center for Disease Control and PreventionBeijing 100050China Abstract Objective To establish a method for detecting perfluorooctanesulfonate PFOS and perfluorooctanoic acid PFOA in three kinds of animal food. Methods Samples were extracted by methanol and cleaned-up by SPE in a WAX 2011-06-03 20607021 E-mail liujiaying17@ yahoo. cn